Holder for acetabular reamer

Abstract

A holder for an acetabular reamer of the type including a generally hemispherical shell having a circular edge and cross arms connected adjacent to the edge and which converge at the center of the edge. The holder includes a base having a datums and at least three pedestals extending up from the base at locations spaced radially from, and distributed about, the datums. Each pedestal has side walls and an upper wall extending between the side walls and facing away from the base. The upper wall is curved so that together the upper walls of the pedestals define an imaginary surface having substantially spherical curvature, so that the pedestals help to retain a reamer whose shell is congruent to the collective upper walls and whose edge is substantially parallel to the base.

What is claimed is:  
     
       1. A holder for an acetabular reamer of the type including a generally hemispherical shell having a circular edge and cross arms connected adjacent to said edge and which converge at the center of said edge, said holder comprising a base having a datums, and at least three pedestals extending up from said base at locations spaced radially from, and distributed about, said datums, each said pedestal having side walls and an upper wall extending between said side walls and facing away from the base, said upper wall being curved so that, together, the upper walls of the pedestals define an imaginary surface having substantially spherical curvature, said pedestals helping to retain a reamer whose shell is more or less congruent to said collective upper walls and whose edge is substantially parallel to said base. 
     
     
       2. The holder defined in claim  1  wherein said upper walls are convex. 
     
     
       3. The holder defined in claim  2  wherein each pedestal is cylindrically curved about said datums and each upper wall has a radially outer bevel and is crowned so that the pedestal is lower at said side walls than at the crown. 
     
     
       4. The holder defined in claim  2  or  3  and further including at least one pair of clips extending up from the base at locations spaced radially from, and distributed about, said datums, said clips having mouths facing away from the base and being arranged and adapted to receive and releasably retain the cross arms of a reamer whose shell is congruent to the collective upper walls of said pedestals. 
     
     
       5. The holder defined in claim  4  wherein said at least three pedestals include a first pair of diametrically opposite pedestals, and a second pair of diametrically opposite pedestals, said first and second pedestal pairs being angularly offset 90° about said datums. 
     
     
       6. The holder defined in claim  5  wherein the pedestals are angularly offset from, but adjacent to, the clips, and the clips are no higher than the side walls of the pedestals so that when a reamer is placed on the holder so that the reamer cross arms engage the upper walls of the pedestals, the weight of the reamer will cause the cross arms to slide down said upper walls until the cross arms are aligned with the mouths of said clips. 
     
     
       7. The holder defined in any one of claims  1  to  3  and further including fastening means for fastening the holder to the support. 
     
     
       8. The holder defined in claim  7  wherein the fastening means comprise a rough hole in said base at said datums, and a fastener sized to extend into the hole to fasten the base to a support. 
     
     
       9. The holder defined in claim  8  wherein said hole is tapered and said fastener comprises a head and a split shaft extending from the head, said shaft being tapered correspondingly to said hole. 
     
     
       10. The holder defined in claim  1  wherein said upper walls are concave. 
     
     
       11. The holder defined in claim  10  wherein said at least three pedestals include a first pair of diametrically opposite pedestals and a second pair of diametrically opposite pedestals, said first and second pedestal pairs being angularly offset 90° about said datums. 
     
     
       12. The holder defined in claim  7  and further including fastening means for fastening said holder to a support. 
     
     
       13. The holder defined in claim  12  wherein said fastening means includes a through hole in said base at said datums, and a fastener sized to extend into said hole to fasten the base to a support. 
     
     
       14. The holder defined in claim  13  wherein said hole is tapered, and said fastener comprises a head and a split shaft extending from the head, said shaft being tapered are correspondingly to said hole.